• Title/Summary/Keyword: Automotive noise

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Study on the Effects of Noise for the Electric Motor according to Slot Open (슬롯 오픈이 전동기 소음에 미치는 영향 고찰)

  • Kim, Su-Chul;Kim, Kyu-Sik;Lee, Byong-Hwa;Park, Kwang-Min;Lee, Bong Hyun;Hong, Jung-Pyo
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.843-844
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    • 2015
  • 본 논문은 매입형 영구자석 동기모터(IPMSM: Interior Permanent Magnet Synchronous Motor)에서 발생하는 소음의 원인을 유추하고 해석적, 실험적 방법을 통하여 소음을 평가한다. 또한 비교 모델의 실험을 수행하여 측정된 데이터에 따른 소음 값을 비교 분석한다. 대상 모델은 12극 18슬롯이고 슬롯 오픈의 유무에 따른 주파수 분석 및 소음을 측정하였다. 기존 전동기와 비교 모델 전동기의 소음 결과를 분석하였고 슬롯 오픈 유무에 따라 소음이 발생하는 것을 확인하였다.

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Evaluation and improvement of the vibrational characteristics in the automotive exhaust system (자동차 배기계의 진동특성의 평가 및 개선에 관한 연구)

  • Park, H;Jeon, E. S.;Oh, J. E.;Lim, D. G.
    • Journal of the korean Society of Automotive Engineers
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    • v.12 no.4
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    • pp.47-55
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    • 1990
  • This study is the first step for the grasp of transfer path to the vibration generated from the automotive engine and consideration of counterplan for optimal design and low vibration, low noise of the exhaust system. In this study, by applying the theory of modal analysis and experiment, vibrational reduction effect is evaluated according to the attachment of flexible coupling to the exhaust system. And data for the design is suggested to improve the characteristics of vibration. The vibration isolation and damping characteristics are improved due to the attachment of flexible coupling to the exhaust system. As a result, it is identified that flexible coupling which has good flexibility is more effective for the improvement of vibrational characteristics. By the estimation of modeshape of vibration, the location of optimal damping hanger is determined in the viewpoint of vibration isolation. Also it is confirmed that the characteristics of vibration is improved due to the attachment of damping hanger.

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A Study for a Automotive Neutral Gear Rattle and the Clutch Torsional Characteristics (자동차 공회전시 기어래틀과 클러치 비틀림특성에 대한 연구)

  • Hong, D.P.;Chung, T.J.;Tae, S.H.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.2
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    • pp.30-41
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    • 1995
  • Gear rattle is a source of vibration and noise in automotive gearbox casing and generally occurs at or near system resonant frequencies. The neutral gear rattle of the gearbox. is affected by the stiffness and hysteresis torque in the clutch disk and drag torque determining balancing point of the clutch disk operating range. The experiment is carried out in the pre-damper type clutch and a manual transmission of a automobile equipped for inline four-sylinder four-cycle 1.5L MPI engine and the computer simulation is executed by 5th order Runge-Kutta method. The results of the simulation analysis and experimental studies show the dynamic behavior of clutch and a phenomenon of the neutral gear rattle with respect to drag torque and torsional characteristics of the clutch.

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Study on Performances of the Lever Type Anti-resonance Vibration Isolator (레버형 반공진 진동 절연기의 진동 특성 연구)

  • Yun, Jong-Hwan;Kim, Gi-Woo;Lee, Hyeongill
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.2
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    • pp.187-194
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    • 2016
  • Parametric study on the lever type dynamic anti-resonance vibration isolator (DAVI) is executed to introduce the system in the path of vibration transmission for the vibratory response attenuation. The effects of inertia and location of the lever on the system performances are investigated using FEA. The effects of other parameters such as ratio of lever lengths, ratio of masses and the location of pivot are studied with analytical approach. According to the results, all the parameters except lever location affect the system response in their own ways. Consequently, the optimal lever type DAVI for translational or rotational system can be efficiently designed by selecting system parameters using the procedure introduced in this study.

A Study on Quantitiative visualization of Vibration Mode Shape of Disk Brake by Using Stroboscopic ESPI (스트로보스코픽 전자 스페클 패턴 간섭법을 이용한 디스크 브레이크의 진동 모드의 정량적 가시화에 관한 연구)

  • 강영준
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.9
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    • pp.97-104
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    • 1999
  • Brake squeal noise has been a problem since the early days of motoring . It is important to obtain vibration mode shape for reduction of brake noise . Stroboscopic Electronic Speckle Pattern Interferometry is a very powerful measuring method for study of vibrating objects in static state compared with conventional methods because this method can give both resonance frequency and quantitative visualization of vibration mode shape at the same time. In this paper, we performed qualitative visualization and quantitative analysis of vibration mode shpae of disk brake by using stroboscopic ESPI and phase shifting method. The stroboscopic wavefronts are obtained by chopping continuous wave laser beam using acousto-optic modulator .Experiments were performed at the same constraint conditions as disk brake of the practical vehicle as far as possible. The experimental results of this paper show quantitative measurement of vibration mode shape and quantiative visualization of vibration amplitude of disk brake with 3D plotting.

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The Development of Muffler with Controller Sensing Exhaust Gas Pressure in Automobile Exhaust System(1) -The general characteristics of exhaust system and characteristics of control valve- (자동차 배기계의 배기압 감응형 제어 머플러 개발(1) -배기계의 일반 특성과 제어 밸브의 특성-)

  • 이해철;이준서;윤준규;차경옥
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.1
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    • pp.37-44
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    • 2001
  • This study is focused on the development of a new muffler. A control valve installed in the exhaust system is operated by torsion springs, and its open angle is controlled automatically corresponding to the engine operating conditions. The experiments were done using an exhaust system simulator having the same pulsation wave frequency and similar pulsation propagation characteristics of a real exhaust system. The purpose of this study is to develop a new muffler system which has improved noise reduction quality and less power loss than conventional mufflers and electronic-control mufflers.

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DEVELOPMENT OF A SOUND QUALITY INDEX FOR THE EVALUATION OF BOOMING NOISE OF A PASSENGER CAR BASED ON REGRESSIVE CORRELATION

  • LEE J. K.;PARK Y. W.;CHAI J. B.;JANG H. K.
    • International Journal of Automotive Technology
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    • v.6 no.4
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    • pp.367-374
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    • 2005
  • This paper proposes a sound quality index to evaluate the vehicle interior noise. The index was developed using a correlation analysis of an objective measurement and a subjective evaluation data. First, the objective set of measurements was obtained at two specified driving conditions. One is from a wide-open test condition and the other is from a constant-speed test condition. At the same time, subjective evaluation was carried out using a score of ten scale where 17 test engineers participated in the experiment. The correlation analysis between the psycho-acoustic parameters derived from the objective measurement and the subjective evaluation was performed. The most critical factors at both test conditions were determined, and the corresponding equations for the sound quality were obtained from the multiple factor regression method. Finally, a comparative work between previous index and present index was performed to validate the effectiveness of the proposed index.

Prediction of Vehicle Exhaust Noise using 3-Dimensional CFD Analysis (3차원 유동해석을 통한 차량 배기소음 예측에 관한 연구)

  • 진봉용;이상호;조남효
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.5
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    • pp.148-156
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    • 2001
  • Computational Fluid Dynamics (CFD) analysis was carried out to investigate exhaust gas flow and acoustic characteristics in the exhaust system of a passenger car. Transient 3-dimensional flow field in the front and rear mufflers was simulated by CFD and far-field sound pressure was modeled by a simple monopole source method. Engine performance simulation was also performed to obtain the boundary condition of instantaneous fluid flow variation at the inlet of the exhaust system. Detailed exhaust gas flow characteristics such as velocity and pressure distribution inside the mufflers were presented and the pulsating pressure amplitude was compared at several positions in the exhaust system to deduce sound pressure level. The present method of the acoustic analysis coupled with CFD techniques would be very effective for the prediction of sound noise from vehicle exhaust systems although the effects of the inlet boundary condition and heat transfer on the accuracy of the prediction have to be validated through further studies.

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Unstable Brake Pad Mode Due to Friction-velocity Slope (마찰 곡선에 의한 불안정 브레이크 패드 모드 해석)

  • Nam, Jaehyun;Kang, Jaeyoung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.12
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    • pp.1206-1212
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    • 2012
  • The brake squeal propensity due to the friction-velocity curve is numerically investigated. The finite element models for the disc and pad are correlated with the modal test. In the friction-engaged system modeling, the friction function is linearized at the equilibrium. The damping term induced by friction-velocity slope is incorporated into the equations of motion. In the complex eigenvalue analysis, it is found that the pad shear mode is very sensitive to the friction curve. The results shows that the squeal propensity of the pad shear mode can be controlled by the design parameters such as pressure and stiffness.

A Study on an Optimal Design of Engine Mount System (엔진 마운트계의 최적설계에 관한 연구)

  • 황원걸
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.1
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    • pp.16-26
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    • 1998
  • The major effective factors on the ride quality of a vehicle are the vibration and noise of the engine and drive system. Engine contributes about 80% of the vibration and noise in the vehicle, and exciting forces of the engine are transmitted onto the vehicle frame through the engine mount. This paper studies the vibration reduction of a vehicle through the improvement of the engine mount. A computer program for optimal design is developed and the engine mount conditions are optimized to reduce the WRMS of PSD of acceleration at the driver's seat, which are caused by the exciting forces at the idle speed. Design variables are selected as the stiffness, mount angle and the location of the engine mount rubber. It is shown through computer simulation that the PSD of acceleration at the driver's seat can be improved by redesigning the engine mount system.

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